I monitored Great Tinamou (Tinamus major) clutches between February and May 2000–2002 at La Selva Biological Station in Costa Rica, and describe observations on incubation behavior and nest attendance. Incubation lasted 17 days and began after the clutch was completed. Nest attendance during monitoring was high: birds were incubating during 249 nest checks at all incubation stages. Only five of 18 incubating birds that were monitored (34,282 min) with video and photographic cameras left the nest for a combined 257 min. There was no pattern to time of day or length of time when incubating birds left the nest. DNA from seven incubating birds was used to identify gender and all were males. All birds that sat on clutches defended their eggs and subsequent chicks, but were not recorded standing up to turn their eggs. High nest attendance and reduced parental activity at the nest may reduce nest detection by predators.